require "inch/utils/shell_helper"

module Inch
  module CLI
    module Command
      module Options
        class Diff < BaseObject
          include Utils::ShellHelper

          def initialize
            @before_rev = "HEAD"
            @after_rev  = nil
          end

          def descriptions
            [
              "",
              "Shows changes in documentation between two revisions " \
                "(defaults to last commit against current)",
              "",
              "Example: " + "$ inch diff HEAD^..HEAD".color(:cyan),
              "",
              description_hint_grades,
              description_hint_arrows
            ]
          end

          def set_options(opts)
            diff_options(opts)
            common_options(opts)
          end

          # @return [Array<String>] the revisions to be diffed
          #   nil meaning the current working dir, including untracked files
          #   since these are later parsed via `git rev-parse`, we can support
          #   notations like "HEAD" or "HEAD^^"
          #
          # @example
          #   revisions # => ["HEAD", nil]
          def revisions
            if object_names.empty?
              [@before_rev, @after_rev]
            else
              object_names.first.split("..")
            end
          end

          def since_last_commit?
            revisions == ["HEAD", nil]
          end

          def since_last_push?
            @since_last_push == true
          end

          private

          def diff_options(opts)
            opts.separator ""
            opts.separator "Diff options:"

            opts.on("--since-last-commit",
                    "Run diff against last commit (default)") do
              @before_rev = "HEAD"
            end
            opts.on("-p", "--since-last-push",
                    "Run diff against last pushed commit") do
              @before_rev = pushed_rev
              @since_last_push = true
            end
          end

          # @return [String] the reference for the pushed revision
          #
          # @example
          #   pushed_rev # => "origin/master"
          def pushed_rev
            "#{remote}/#{current_branch}"
          end

          def current_branch
            git Dir.pwd, "rev-parse --abbrev-ref HEAD"
          end

          def remote
            "origin"
          end
        end
      end
    end
  end
end